TL = technical level
You have versions and releases and i suppose you know about these. Below this are "technical levels", which (very roughly) correspond to what is known as a "service pack" in WIndows: a lot of bugfixes and minor corrections made over time bundled into a "mini-release". Back then these have been called "maintenance levels" ("ML"), which was basically the same, but IBM is in the habit of renaming anything every few years.

Get the current TL by issuing (as root):

Code:

instfix -i | grep AIX_TL

Note, that the oslevel command only shows the latest completely installed TL. If you have parts of a newer TL installed it will show in the instfix command, but not in oslevel. See the pinned thread in the AIX forum for details.

PowerHA = SystemMirror = HACMP
Seaking about renaming things: this is the cluster software for AIX and - see above - known under quite a few names. All these names describe exactly the same product, just renamed. The AIX cluster is a very reliable, very stable, very versatile piece of software, but rather costly. Still, i would rely for mission-critical systems on nothing else, it is money well invested. If done and maintained correctly we are talking about the type of systems where one outage every ten years is considered shoddy work.

PowerVM = the IBM hypervisor
This is the IBM hypervisor and basis of IBMs virtualisation. It is way faster than anything else in the market and with unparalleled data throughput, but it supports Linux only as LPAR. You can use PowerKVM (the KVM implementation on Power) instead, but then only Linux containers/LPARs are supported and it is slower than PowerVM. Basically PowerVM is (built into the hardware and used by) the VIOS, the HMC and their workings.

See above, not quite, although VIOS is a part of it.

I hope this helps.

bakunin